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Re: [IP] basal question

Neal & Kara wrote:
> Where does the glucose that the basal rate is supposed to counter come from?
> Is it a background glucose put out by your body (liver) REGARDLESS  of food
> you eat, or rather does depend, even a little, on food you eat that doesn't
> quite convert into sugar quick enough to be covered by a bolus?

Neal, Kara -

Further to what Ted wrote, insulin does many different things in the body.
It doesn't just push glucose out of the blood. The actual concentration of
insulin in the blood sends out the signals and determines what the insulin
should do.

At a very high level, insulin takes glucose from the blood and stores it as
fat. So large boluses, rather than large amounts of food, cause you to put
on weight.

At a lower level, it stores the blood glucose as glycogen in the liver and
muscles. Glycogen is essentially an insoluble form of glucose. Glycogen is
the first energy source you body draws on when you start exercising, since
it's already stored within the muscle cell.

At a yet lower level, insulin does nothing. It just holds everything
steady. This is the level your basal rate should be set to achieve.

At an even lower level, the lack of insulin sends a signal to the liver to
release its glycogen into the blood as glucose. Up to now the insulin has
been holding the glycogen in place. Now it just floods out. In the
non-diabetic, the rising bg will cause more insulin to be made, stopping it
rising too far. For us it just keeps rising. So when your infusion set
falls out, the liver interprets the lack of insulin as a signal that lots
of glucose is needed, so the bg rises rapidly even though you've eaten
nothing. This is known as "dumping".

At a very low level, the lack of insulin causes fat to breakdown, and
release energy into the blood. Acidic by-products are released, which
ultimately causes DKA.

This is an extreme simplification of a complex and dynamic system. Any
knock to the system, like a hypo, or adrenaline, can change the levels at
which different things happen. Even with a pump, we still have very crude
control. To make matters worse, since we introduce the insulin into outer
circulation, we bathe the muscles in too much insulin, and give the liver
too little. So you can simultaneously give conflicting signals to different
parts of the body. That's why diabetes can still be such a bugger to
control at times, even with the best technology.

Hope some of this makes sense.


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